Manual paper feed device, image forming apparatus, and image forming method

ABSTRACT

A manual paper feed device includes: a manual feed tray on which sheets are stacked; a paper feeding roller that feeds the sheets on the manual feed tray into an image forming unit; a pressing tray that is, with the sheets stacked thereon, rotatably supported and a downstream side of which in a conveying direction of the sheets is biased to the paper feeding roller side; a bias releasing member that separates and holds the pressing tray in a direction opposed to the bias direction and releases the biasing; and a sensor that detects at least one of presence or absence of the sheets on the manual feed tray and a bias releasing state of the pressing tray. The manual paper feed device prohibits paper feeding operation when the bias releasing state of the pressing tray is detected regardless of presence or absence of sheets stacked on the pressing tray.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from U.S. provisional application 61/079,728, filed Jul. 10, 2008, the entire contents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a manual paper feed device, an image forming apparatus, and an image forming method for notifying information concerning the stop of paper feeding operation of a manual paper feed unit.

BACKGROUND

Among image forming apparatuses such as a copying machine, an MFP (Multi Function Peripheral), and a printer, there is an image forming apparatus that includes, as a supply source of recording sheets, a manual paper feed device including a manual feed tray separately from a paper feeding cassette. In the image forming apparatus, the manual feed tray is arranged to project in a lateral direction of an apparatus main body. Recording sheets stacked in the manual feed tray are delivered to a sheet feeding mechanism in the apparatus main body of the image forming apparatus. In general, taking into account space saving, the manual feed tray itself is formed to be retractable in the apparatus main body when not in use. For example, JP-A-2003-201025 discloses a manual paper feed device that, when a user operates a pressing lever to release a lock state of a bottom plate, pushes up the bottom plate, on which recording sheets are stacked, to a paper feeding roller side and feeds the recording sheets.

In such a manual paper feed device for an image forming apparatus, if the user drives the paper feeding roller without releasing a push-down state of the bottom plate even in a state in which a sheet residual amount detection sensor on the bottom plate detects a state of presence of sheets, paper feeding by the paper feeding roller cannot be performed. Therefore, when the user forgets to release push-down of the bottom plate, the image forming apparatus performs processing for a paper jam.

There is also an image forming apparatus including a sensor that detects the top of recording sheets to detect presence or absence of recording sheets only in a state in which push-down of a bottom plate is released. The image forming apparatus is configured to perform paper feeding operation only in a state in which the push-down of the bottom plate is released and the presence of recording sheets is detected. In the image forming apparatus, when recording sheets are stacked to an upper limit number of sheets in specifications of a manual feed tray, even in a state in which the bottom plate is pushed down, the sensor that detects the top of recording sheets misdetects, because of curl or the like of the recording sheets, that the recording sheets are present and drives the paper feeding roller.

SUMMARY

The present invention has been devised in view of the circumstances and it is an object of the present invention to provide a manual paper feed device, an image forming apparatus, and an image forming method for determining whether the stop of paper feeding operation of a manual paper feed unit is caused by the absence of recording sheets or misoperation of a paper feeding mechanism and notifies a user of the cause.

In order to attain the object, according to an aspect of the present invention, there is provided a manual paper feed device including: a manual feed tray configured to stack a sheet; a paper feeding roller configured to feed the sheets on the manual feed tray into an image forming unit; a pressing tray configured to stack the sheet, rotatably supported with a first pivoting shaft as a first fulcrum and a downstream side of which in a conveying direction of the sheet is biased to the paper feeding roller side; a bias releasing member configured to separate and hold the pressing tray in a direction opposed to the bias direction and release the biasing; a sensor configured to detect at least one of presence or absence of the sheet on the manual feed tray and a bias releasing state of the pressing tray; a switching member configured to switch a biasing state and the bias releasing state of the pressing tray, coupled to the bias releasing member; a first detected member rotatably supported with a second pivoting shaft as a second fulcrum in contact with the sheet on the pressing tray, and provided in a position detectable by the sensor when the sheet is not present on the pressing tray; and a second detected member provided in a position detectable by the sensor when the pressing tray is in the bias releasing state.

In order to attain the object, according to another aspect of the present invention, there is provided an image forming apparatus including a manual paper feed device configured to be retractable in an apparatus main body, including: a manual feed tray configured to stack a sheet; a paper feeding roller configured to feed the sheet on the manual feed tray into an image forming unit; a pressing tray configured to stack the sheet, rotatably supported with a first pivoting shaft as a first fulcrum and a downstream side of which in a conveying direction of the sheet is biased to the paper feeding roller side; a bias releasing member configured to separate and hold the pressing tray in a direction opposed to the bias direction and release the biasing; a sensor configured to detect at least one of presence or absence of the sheet on the manual feed tray and a bias releasing state of the pressing tray; a switching member configured to switch a biasing state and the bias releasing state of the pressing tray, coupled to the bias releasing member; a first detected member rotatably supported with a second pivoting shaft as a second fulcrum in contact with the sheet on the pressing tray, and provided in a position detectable by the sensor when the sheet is not present on the pressing tray; a second detected member provided in a position detectable by the sensor when the pressing tray is in the bias releasing state; a determining unit configured to determine a state of the manual paper feed device on the basis of a detection signal of the sensor; and a notifying unit configured to notify a result of the determination by the determining unit.

In order to attain the object, according to still another aspect of the present invention, there is provided an image forming method including: generating a detection signal in at least one of a state in which the sheet is not present on a pressing tray of a manual paper feed device, that is biased to a paper feeding roller side with the sheet stacked thereon and a bias releasing state of the pressing tray; determining, on the basis of the detection signal, at least one of the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray; stopping driving of the paper feeding roller according to the determination; and notifying a result of the determination.

DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a diagram of an external appearance example of a typical example of an image forming apparatus according to a first and a second embodiment of the present invention;

FIG. 2 is a perspective view of the structure of a manual paper feed unit included in the image forming apparatus according to the first and the second embodiment;

FIG. 3 is a schematic side view of the structure of the manual paper feed unit and an image processing unit included in the image forming apparatus according to the first embodiment;

FIG. 4 is a schematic side view of the structure of the manual paper feed unit and the image processing unit included in the image forming apparatus according to the first embodiment;

FIG. 5 is a schematic side view of the structure of the manual paper feed unit and the image processing unit included in the image forming apparatus according to the first embodiment;

FIG. 6 is a schematic side view of the structure of the manual paper feed unit and the image processing unit included in the image forming apparatus according to the first embodiment;

FIG. 7 is a table of determination by a processor of the image forming apparatus according to the first embodiment for each of the states of the manual paper feed unit shown in FIGS. 3 to 6;

FIG. 8 is a schematic side view of the structure of a manual paper feed unit and an image processing unit of the related art;

FIG. 9 is a table of determination by a processor for each of the states of the manual paper feed unit shown in FIG. 8;

FIG. 10 is a schematic side view of the structure of a manual paper feed unit and an image processing unit included in an image forming apparatus according to the second embodiment of the present invention;

FIG. 11 is a schematic side view of the structure of the manual paper feed unit and the image processing unit included in the image forming apparatus according to the second embodiment;

FIG. 12 is a schematic side view of the structure of the manual paper feed unit and the image processing unit included in the image forming apparatus according to the second embodiment;

FIG. 13 is a schematic side view of the structure of the manual paper feed unit and the image processing unit included in the image forming apparatus according to the second embodiment; and

FIG. 14 is a table of determination by a processor of the image forming apparatus according to the second embodiment for each of the states of the manual paper feed unit shown in FIGS. 10 to 13.

DETAILED DESCRIPTION

Embodiments of the present invention are explained below with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a diagram of an external appearance example of an MFP as a typical example of an image forming apparatus according to a first embodiment of the present invention.

An image forming apparatus 10 according to the first embodiment is shown in FIG. 1. The image forming apparatus 10 includes an apparatus main body (an image forming unit) 11, an auto document feeder (ADF) 12, and a manual paper feed unit 13. The apparatus main body 11 includes an operation unit 21, an image reading unit 22, paper feeding cassettes 23, and an image forming unit 24. Although not shown in the figure, the image forming apparatus 10 includes a processor including a CPU (Central Processing Unit). The image forming apparatus 10 may be a PPC (Plain Paper Copier), or a printer.

In the image forming apparatus 10, the auto document feeder 12 is provided in an upper part of the apparatus main body 11. The operation unit 21 is provided on the front side of the image forming apparatus 10. The operation unit 21 includes, for example, a touch panel display. The operation unit 21 also has a role of an operation input unit that receives operation and job setting input of a user based on display content in the operation unit 21.

In the image forming apparatus 10, the paper feeding cassettes 23 in several stages (in FIG. 1, four stages) that can be drawn out to the front side are provided in a lower part of the apparatus main body 11. In each of the paper feeding cassettes 23, plural sheets are stacked and stored.

In the image forming apparatus 10, the manual paper feed unit 13 is provided on a side of the apparatus main body 11. A manual feed tray 131 of the manual paper feed unit 13 has the structure openable and closable with respect to the apparatus main body 11 with a rotating shaft thereof supported by the apparatus main body 11. The manual feed tray 131 is retractable in the apparatus main body 11 by user operation. When the user places recording sheets on the manual feed tray 131 in a state in which the manual feed tray 131 is opened from the apparatus main body 11, the manual paper feed unit 13 feeds the recording sheets to the image forming unit 24 one by one.

From the viewpoint of information security in recent years, for example, in copying (predetermined image forming processing) using the image forming apparatus 10, first, the image forming apparatus 10 performs user authentication processing in an authentication processing unit 21 a of the operation unit 21. Subsequently, the auto document feeder 12 automatically conveys an original document on a tray to a document reading position of the image reading unit 22 on the basis of operation input to the operation unit 21 by a user who succeeds in the authentication processing. The image reading unit 22 reads an image of the original document conveyed by the auto document feeder 12.

The paper feeding cassette 23 or the manual paper feed unit 13 performs paper feeding operation according to a paper feeding method selected on the basis of operation input to the operation unit 21. The paper feeding cassette 23 or the manual paper feed unit 13 conveys a recording sheet to the image forming unit 24. The image forming unit 24 copies image data read by the image reading unit 22 to the recording sheet.

FIG. 2 is a perspective view of the structure of the manual paper feed unit 13. In FIG. 2, the manual paper feed unit 13 that can feed recording sheets to the image forming unit 24 and stores no recording sheet is shown. FIGS. 3 to 6 are side views of the schematic structure of the manual paper feed unit 13 and the image forming unit 24.

The manual paper feed unit 13 includes the manual feed tray 131, a paper feeding roller 132, a separation pad 133, a pressing tray 134, a rib 135, a sensor 136, a slider 137, a switching lever 138, an actuator 139 as a member detected by the sensor 136, and a second detected member (hereinafter referred to as shield rib) 140.

Recording sheets P are stacked on the manual feed tray 131.

The paper feeding roller 132 passes the recording sheets P on the manual feed tray 131 to registration rollers 241 configuring a conveying mechanism of the image forming unit 24.

The separation pad 133 is fixed to a separation pad holder 133 a (see FIG. 3; not shown in other figures). The separation pad 133 is biased to the paper feeding roller 132 side and separates the recording sheets P one by one in a press contact portion with the paper feeding roller 132. When a registration sensor 242 provided in a sheet conveying section of the image forming unit 24 detects the recording sheet P that the registration rollers 241 receive from the paper feeding roller 132 and the separation pad 133, the registration sensor 242 generates a detection signal and notifies the processor of the detection. The processor pivots, a predetermined time after the registration sensor 242 detects the leading end of the recording sheet P, the registration rollers 241 to convey the recording sheet P to the image forming unit 24.

The pressing tray 134 is supported by the apparatus main body 11 via a pivoting shaft 134 a and is pivotable with the pivoting shaft 134 a as a fulcrum. A leading end portion in a paper feeding direction of the recording sheet P on the manual feed tray 131 is placed on the pressing tray 134. A pressing spring 134 b (see FIG. 2; e.g., a compression coil spring) as an elastic member, one end of which is fixed to a bottom surface of the rib 135, brings the other end thereof into contact with a rear surface on a downstream side of the pressing tray 134 and presses and biases the downstream side of the pressing tray 134 in an arrow Q direction (to the paper feeding roller 132 side). When the recording sheet P is present on the manual feed tray 131, the pressing tray 134 is biased by the pressing spring 134 b and presses the recording sheet P against the paper feeding roller 132.

The sensor 136 is set on a lower surface (a rear surface side on which the recording sheets P are not placed) of the pressing tray 134. A detecting unit of the sensor 136 faces the actuator 139 as the detected member and the shield rib 140 as the second detected member. When the detecting unit of the sensor 136 detects at least one of the actuator 139 and the shield rib 140, the detecting unit generates a detection signal and notifies the processor of the detection.

The slider 137 is slidably provided in the manual feed tray 131. The slider 137 has an engaging section D2. The slider 137 engages the engaging section D2 with an engaging section D1 of the pressing tray 134 and tugs the engaging section D1 of the pressing tray 134 in an opposite direction of a sheet conveying direction according to the movement in the sheet conveying opposite direction of the slider 137. The pressing tray 134 pivots with the pivoting shaft 134 a as a fulcrum according to the movement in the sheet conveying opposite direction of the engaging section D1 of the pressing tray 134. The downstream side of the pressing tray 134 separates from the paper feeding roller 132 in a direction opposed to the bias direction Q of the pressing spring 134 b and maintains a separated state (a lock mechanism).

The switching lever 138 is pivotably supported by the manual feed tray 131 via a pivoting shaft (not shown in the figure). When the user operates the switching lever 138 to pivot the switching lever 138, the slider 137 slides in the sheet conveying direction (an unlock state of a paper feeding operation) or the sheet conveying opposite direction (a lock state of the paper feeding operation) in the manual feed tray 131. The user can switch, by operating the switching lever 138, the manual paper feed unit 13 to a state in which the recording sheets P can be fed to the image forming unit 24 (the unlock state of the paper feeding operation) and a state in which the recording sheets P cannot be fed to the image forming unit 24 (the lock state of the paper feeding operation).

In the unlock state of the paper feeding operation, the maintenance of the separation of the pressing tray 134 is released and the pressing tray 134 is set free and biased to the paper feeding roller 132 side by the pressing spring 134 b (see FIG. 2; not shown in other figures). In this case, the paper feeding operation can be executed. In the lock state of the paper feeding operation, the pressing tray 134 is separated in a direction opposed to the bias direction Q of the pressing spring 134 b and maintained in a separated state.

The actuator 139 is supported by the bottom of the rib 135 via a pivoting shaft 139 a and can pivot with the pivoting shaft 139 a as a fulcrum. The actuator 139 is biased in an arrow R direction on the pressing tray 134 side by an elastic member (not shown in the figure; e.g., a torsion spring) attached to the pivoting shaft 139 a. The actuator 139 is formed to be detected by the detecting unit of the sensor 136 when the recording sheets P are not present on the pressing tray 134 regardless of the lock state or the unlock state of the paper feeding operation.

As shown in the figure, the shield rib 140 has a curvature section that does not hinder a pivoting track of the pressing tray 134. The shield rib 140 is formed to be detected by the detecting unit of the sensor 136, which is set on the bottom surface of the pressing tray 134, in the lock state of the paper feeding operation, i.e., the pressing tray 134 is separated and present in a lock position.

First State of the Manual Paper Feed Unit 13

A first state of the manual paper feed unit 13 that can feed the recording sheets P to the image forming unit 24 and stores no recording sheet P is shown in FIG. 3. Specifically, the first state of the manual paper feed unit 13 is a state in which the recording sheets P in the manual paper feed unit 13 are exhausted during copy, a state of the end of the copy, or a state of a wait for the supply of the recording sheets P before the start of the copy.

As shown in FIGS. 2 and 3, the first state of the manual paper feed unit 13 is the unlock state of the paper feeding operation. The downstream side of the pressing tray 134 is biased to the paper feeding roller 132 side by the pressing spring 134 b. In the first state of the manual paper feed unit 13, since the recording sheets P are not present on the pressing tray 134, the downstream side of the pressing tray 134 comes into direct contact with the paper feeding roller 132 side.

In the first state of the manual paper feed unit 13, since the recording sheets P are not present on the pressing tray 134, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 detects the actuator 139 and generates an actuator detection signal. Since the first state of the manual paper feed unit 13 is the unlock state of the paper feeding operation, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 does not detect the shield rib 140. The actuator detection signal is transmitted to the processor.

Second State of the Manual Paper Feed Unit 13

A second state of the manual paper feed unit 13 that cannot feed the recording sheets P to the image forming unit 24 and stores no recording sheet P is shown in FIG. 4. Specifically, the second state of the manual paper feed unit 13 is the lock state of the paper feeding operation in which the user pivots the switching lever 138 in an arrow S direction to slide the slider 137, whereby the pressing tray 134 is separated from the paper feeding roller 132 and held. In other words, the second state is a state in which the recording sheets P can be supplied to the manual feed tray 131 of the manual paper feed unit 13 and a state before the user places the recording sheets P on the manual feed tray 131 on which the recording sheets P are not stacked. In the case of the lock state of the paper feeding operation like the second state of the manual paper feed unit 13, even if the recording sheets P are stacked on the pressing tray 134 (a state shown in FIG. 5), it is necessary to detect that the paper feeding operation cannot be executed.

As shown in FIG. 4, in the second state of the manual paper feed unit 13, the pressing tray 134 is separated in a direction opposed to the bias direction Q by the pivoting of the switching lever 138 and separated from the paper feeding roller 132 and held (the lock state of the paper feeding operation). The downstream side of the pressing tray 134 is separated from the paper feeding roller 132 and locked against the biasing force of the pressing spring 134 b.

In the second state of the manual paper feed unit 13, since the recording sheets P are not present on the pressing tray 134, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 detects the actuator 139 biased to pivot in the arrow R direction and generates an actuator detection signal. Further, since the second state of the manual paper feed unit 13 is the lock state of the paper feeding operation in which the pressing tray 134 is separated from the paper feeding roller 132 and held, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 detects the shield rib 140 and generates a shield rib detection signal. The detection signals are transmitted to the processor. As shown in FIG. 4, the single sensor 136 is arranged to be capable of detecting both the actuator 139 and the shield rib 140 functioning as the detected members. However, in the second state of the manual paper feed unit 13, the sensor 136 may detect only the shield rib 140. This can be easily realized by forming the actuator 139 in a shape for preventing the actuator 139 biased in the R direction in the recording sheet absent state from being detected by the detecting unit of the sensor 136 when the pressing tray 134 is separated and held (now shown in the figure; e.g., an external shape for avoiding the detecting unit or a hole, a cutout portion, or a transparent portion is provided in the actuator 139).

Third State of the Manual Paper Feed Unit 13

A third state of the manual paper feed unit 13 that cannot feed the recording sheets P to the image forming unit 24 and stores the recording sheets P is shown in FIG. 5. Specifically, the third state of the manual paper feed unit 13 is a state after the user places the recording sheets P on the manual paper feed unit 13. As shown in FIG. 5, in the third state of the manual paper feed unit 13, as in the second state of the manual paper feed unit 13, the downstream side of the pressing tray 134 is separated from the paper feeding roller 132 in the direction opposed to the bias direction Q. In the third state of the manual paper feed unit 13, as shown in the figure, when the recording sheets P are stacked in the manual feed tray 131 and the pressing tray 134, the actuator 139 comes into contact with the end of the recording sheets P. Therefore, since the actuator 139 pivots in the opposite direction of the arrow R with the pivoting shaft 139 a as a fulcrum and retracts from the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134, the detecting unit of the sensor 136 does not detect the actuator 139. However, since the third state of the manual paper feed unit 13 is the lock state of the paper feeding operation, the detecting unit of the sensor 136 detects the shield rib 140 and generates a shield rib detection signal. The shield rib detection signal is transmitted to the processor.

Fourth State of the Manual Paper Feed Unit 13

A fourth state of the manual paper feed unit 13 that can feed the recording sheets P to the image forming unit 24 and stores the recording sheets P is shown in FIG. 6. Specifically, the fourth state of the manual paper feed unit 13 is a standby state for the start of image formation, for example, copying.

As shown in FIG. 6, the fourth state of the manual paper feed unit 13 is the unlock state of the paper feeding operation. As in the first state of the manual paper feed unit 13, the downstream side of the pressing tray 134 is biased in the direction of the paper feeding roller 132 with the pivoting shaft 134 a as a fulcrum by the biasing force of the pressing spring 134 b. In this case, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 is separated from the shield rib 140. In the fourth state of the manual paper feed unit 13, since the recording sheets P are present on the pressing tray 134, the top of the recording sheets P on the pressing tray 134 comes into direct contact with the paper feeding roller 132.

In the fourth state of the manual paper feed unit 13, since the recording sheets P are present on the pressing tray 134, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 does not detect the actuator 139. Since the fourth state of the manual paper feed unit 13 is the unlock state of the paper feeding operation, the detecting unit of the sensor 136 set on the lower surface of the pressing tray 134 does not detect the shield rib 140 either.

FIG. 7 is a table of determination by the processor for each of the states of the manual paper feed unit 13 shown in FIGS. 3 to 6.

As shown in FIG. 7, when the sensor 136 of the manual paper feed unit 13 generates an actuator detection signal (ON) based on the detection of the actuator 139 while the registration sensor 242 detects the recording sheet P (while the recording sheet P is fed and conveyed to the apparatus main body), the processor stops the driving of the paper feeding roller 132 and stops the paper feeding operation according to the actuator detection signal of the sensor 136. The processor determines that the manual paper feed unit 13 shifts to the first state. In that case, the processor notifies, via the operation unit 21, for example, the touch panel display, the user of a warning that the recording sheets P cannot be fed because the recording sheets P are not present. For example, when image data being subjected to copy remains, the processor notifies the user of a request for supply of the recording sheets P. Further, to continue the copy, the user only has to operate the switching lever 138 to supply the recording sheets P and then reset the manual paper feed unit 13 to the fourth state.

When the sensor 136 of the manual feed unit 13 generates the detection signal (ON) while the registration sensor 242 does not detect the recording sheet P (while paper feeding is stopped), the processor determines that the manual paper feed unit 13 is in the second state or the third state and prevents the paper feeding operation by the paper feeding roller 132 from starting. In that case, the processor notifies, via the operation unit 21, for example, the touch panel display, the user of a warning that the recording sheets P cannot be fed because the recording sheets P are not present or the manual paper feed unit 13 is in the lock state of the paper feeding operation. To supply the recording sheets P, the user operates the switching lever 138 to pivot the pressing tray 134 in the direction opposed to the bias direction Q by the pressing spring 134 b and separate the pressing tray 134 from the paper feeding roller 132 and hold the pressing tray 134 (the lock state of the paper feeding operation). The manual paper feed unit 13 shifts from the first state to the second state. Thereafter, when the user supplies the recording sheets P onto the manual feed tray 131, the manual paper feed unit 13 shifts from the second state to the third state. Further, when the user operates the switching lever 138, the manual paper feed unit 13 shifts from the third state to the fourth state. When the registration sensor 242 does not detect the recording sheet P and the sensor 136 does not generate a detection signal, the processor determines that the manual paper feed unit 13 is in the fourth state.

When the registration sensor 242 detects the recording sheet P after a predetermined time elapses from the start of paper feeding by the paper feeding roller 132 and the sensor 136 does not generate a detection signal during the detection (OFF), the processor determines that the manual paper feed unit 13 is feeding the recording sheets P and can feed the recording sheets P and continues the paper feeding by the paper feeding roller 132.

In a state of paper feeding (the recording sheets P are present) in which the sensor 136 does not generate a detection signal, when the registration sensor 242 does not detect the recording sheet P (NO-SIGNAL) even if a predetermined time elapses after the driving of the paper feeding roller 132, the processor stops the paper feeding operation determining that the paper feeding state shifts to a paper jam.

Even if the user attempts to start copying by inputting a restart instruction to the operation unit 21 when the manual paper feed unit 13 is in the lock state of the paper feeding operation, the processor determines, on the basis of a detection signal of the sensor 136, that the manual paper feed unit 13 is in the second state or the third state. In this case, the processor outputs to the user, via the operation unit 21 or the like, a warning that the paper feeding operation is stopped and the recording sheets P cannot be fed to the apparatus main body because the paper feeding operation is locked without starting the paper feeding operation by the paper feeding roller 132 and notifies the user of an operation request for the switching lever 138.

In the first state of the manual paper feed unit 13, when the user transmits a new job signal from a PC and designates manual feed copy, the processor determines that the recording sheets P are not present and informs the user to that effect. In the second state or the third state of the manual paper feed unit 13, when the user transmits a new job signal from the PC and designates the manual feed copy, the processor determines, on the basis of a detection signal of the sensor 136, that the manual paper feed unit 13 is in the lock state of the paper feeding operation. The processor notifies the user of a result of the determination via the operation unit 21, for example the touch panel display or LAN connection without starting the paper feeding operation by the paper feeding roller 132.

FIG. 8 is a side view of the schematic structure of a manual paper feed unit and an image processing unit in the past. In FIG. 8, a state of the manual paper feed unit that can feed the recording sheets P and stores the recording sheets P (equivalent to the third state of the manual paper feed unit 13 according to this embodiment) is shown.

As shown in FIG. 8, the paper feeding operation is locked and the pressing tray 134 is pivoted in the direction opposed to a bias direction by an elastic member (not shown) by the operation of the switching lever 138. The downstream side of the pressing tray 134 is separated from the paper feeding roller 132 against the biasing by the elastic member (not shown). As shown in the figure, an actuator A is set above the recording sheets P to detect a recording sheet at the top. Although not shown in the figure, since the force opposed to the bias direction is released by the unlock of the paper feeding operation, the actuator A comes into contact with the top of the recording sheets P and pivots in the counterclockwise direction. A detecting unit of a sensor C detects the actuator A and generates an actuator detection signal.

FIG. 9 is a table of determination of the processor for each of the states of the manual paper feed unit shown in FIG. 8.

As shown in FIG. 9, when the detecting unit of the sensor C detects the actuator A, the processor causes the paper feeding roller 132 to feed the recording sheets P.

However, as shown in FIG. 8, when the recording sheets P are stacked to an upper limit in specifications of the manual feed tray, a recording sheet may curl in the direction of the actuator A like a recording sheet P′ stacked on the manual feed tray 131. When the detecting unit of the sensor C detects the actuator A raised by the curl, the processor determines that the recording sheets P can be fed and drives the paper feeding roller 132. In such a case, deficiencies in the paper feeding operation such as misfeed of the recording sheets P and a sheet jam occur because of insufficient friction of the paper feeding roller 132.

It is unclear whether the manual paper feed unit cannot feed the recording sheets P because of the absence of the recording sheets P or because of the lock of the paper feeding operation by the switching lever 138. Therefore, the processor notifies, via the operation unit 21 or the like, the user of a wrong warning that the recording sheets P cannot be fed because of a sheet jam.

The manual paper feed unit in the past does not include a configuration for detecting the separation and holding (lock of the paper feeding operation) state of the pressing tray 134. Therefore, the processor determines that the recording sheets P are present and the paper feeding operation is possible even in the lock state of the paper feeding operation. When the paper feeding operation is performed in such a state, the paper feeding roller 132 idles and misfeeds the recording sheets P, the registration sensor 242 does not detect the recording sheets P even if a predetermined time elapses, and the processor determines that a jam occurs. The processor notifies the user of a wrong warning that the recording sheets P cannot be fed to the image forming apparatus because of a sheet jam.

However, the image forming apparatus 10 according to the first embodiment includes the actuator 139, the shield rib 140, and the sensor 136 that detects at least one of the actuator 139 and the shield rib 140. Therefore, the processor determines whether the manual paper feed unit 13 stops the paper feeding operation and the recording sheets P cannot be fed to the image forming apparatus because of the absence of the recording sheets P, because of the lock of the paper feeding operation, or because of a sheet jam and notifies the user of a result of the determination. In the first embodiment, when the sensor 136 detects the lock state of the pressing tray 134, even if, for example, the user inputs a restart instruction via the operation unit 21 without operating the switching lever 138 (releasing the lock) after the recording sheets P are supplied, the processor determines that the manual paper feed unit 13 is in the third state and does not drive the paper feeding roller 132.

With the image forming apparatus 10 according to the first embodiment, even in a state in which the recording sheets P are stacked to the upper limit in specifications of the manual feed tray 131 and the recording sheets P are present, when a detection signal (a signal indicating detection of the lock state of the pressing tray 134) of the sensor 136 is received, the processor does not drive the paper feeding roller 132. In other words, the processor does not drive the paper feeding roller 132 when the detection signal generated by the sensor 136 is received. Therefore, it is possible to prevent malfunction of the paper feeding roller 132. The processor can notify the user of a cause of the stop of the paper feeding operation of the manual paper feed unit 13.

Second Embodiment

An external view example of an image forming apparatus 10A according to a second embodiment of the present invention is the same as the external appearance example of the image forming apparatus 10 according to the first embodiment shown in FIG. 1. The perspective view structure of a manual paper feed unit 13A included in the image forming apparatus 10A according to the second embodiment is the same as the perspective view structure of the manual paper feed unit 13 according to the first embodiment shown in FIG. 2.

FIGS. 10 to 13 are side views of the schematic structure of the manual paper feed unit 13A and the image forming unit 24.

The manual paper feed unit 13A includes the manual feed tray 131, the paper feeding roller 132, the separation pad 133, the pressing tray 134, the rib 135, an actuator sensor 136 a, a shield rib sensor 136 b, the slider 137, the switching lever 138, the actuator 139, and the shield rib 140. In the manual paper feed unit 13A shown in FIGS. 10 to 13, members same as those of the manual paper feed unit 13 shown in FIGS. 3 to 6 are denoted by the same reference numerals and signs and explanation of the members is omitted.

The actuator sensor 136 a is set on the lower surface of the pressing tray 134 and a detecting unit thereof faces the actuator 139 as the detected member. When the detecting unit of the actuator sensor 136 a detects the actuator 139, the detecting unit generates an actuator detection signal (a first detection signal indicating the absence of the recording sheets P) and notifies the processor of the detection.

The shield rib sensor 136 b is set on the lower surface of the pressing tray 134 and a detecting unit thereof faces the shield rib 140 as the second detected member. The shield rib sensor 136 b is annexed to the actuator sensor 136 a. When the detecting unit of the shield rib sensor 136 b detects the shield rib 140, the detecting unit generates a rib detection signal (a second detection signal) and notifies the processor of the detection.

The actuator 139 is formed to be detected by the detecting unit of the actuator sensor 136 a when the recording sheets P are not present on the pressing tray 134 regardless of the lock state or the unlock state of the paper feeding operation.

The shield rib 140 is formed to be detected by the detecting unit of the shield rib sensor 136 b in the lock state of the paper feeding operation, i.e., when the pressing tray 134 is separated and present in the lock position.

First State of the Manual Paper Feed Unit 13 a

A first state of the manual paper feed unit 13A that can feed the recording sheets P to the image forming unit 24 and stores no recording sheet P is shown in FIG. 10.

As shown in FIG. 10, the first state of the manual paper feed unit 13A is the unlock state of the paper feeding operation. The downstream side of the pressing tray 134 is biased to the paper feeding roller 132 side by the pressing spring 134 b. In the first state of the manual paper feed unit 13A, since the recording sheets P are not present on the pressing tray 134, the downstream side of the pressing tray 134 comes into direct contact with the paper feeding roller 132 side.

In the first state of the manual paper feed unit 13A, since the recording sheets P are not present on the pressing tray 134, the detecting unit of the actuator sensor 136 a set on the lower surface of the pressing tray 134 detects the actuator 139 and generates an actuator detection signal. Since the first state of the manual paper feed unit 13A is the unlock state of the paper feeding operation, the detecting unit of the shield rib sensor 136 b set on the lower surface of the pressing tray 134 does not detect the shield rib 140. The actuator detection signal is transmitted to the processor.

Second State of the Manual Paper Feed Unit 13 a

A second state of the manual paper feed unit 13A that cannot feed the recording sheets P to the image forming unit 24 and stores no recording sheet P is shown in FIG. 11. Specifically, the second state of the manual paper feed unit 13A is the lock state of the paper feeding operation in which the user pivots the switching lever 138 in the arrow S direction to slide the slider 137, whereby the pressing tray 134 is separated from the paper feeding roller 132 and held. In other words, the second state is a state in which the recording sheets P can be supplied to the manual feed tray 131 of the manual paper feed unit 13A and a state before the user places the recording sheets P on the manual feed tray 131 on which the recording sheets P are not stacked. In the case of the lock state of the paper feeding operation like the second state of the manual paper feed unit 13A, even if the recording sheets P are stacked on the pressing tray 134 (shown in FIG. 12; even if the manual paper feed unit 13A shifts to the third state), it is necessary to detect that the paper feeding operation cannot be executed.

As shown in FIG. 11, in the second state of the manual paper feed unit 13A, the pressing tray 134 is separated in a direction opposed to the bias direction Q by the pivoting of the switching lever 138 and separated from the paper feeding roller 132 and held (the lock state of the paper feeding operation). The downstream side of the pressing tray 134 is separated from the paper feeding roller 132 and locked (separated and held) against the biasing force of the pressing spring 134 b.

In the second state of the manual paper feed unit 13A, since the recording sheets P are not present on the pressing tray 134, the detecting unit of the actuator sensor 136 a set on the lower surface of the pressing tray 134 detects the actuator 139 biased to pivot in the arrow R direction and generates an actuator detection signal. Further, since the second state of the manual paper feed unit 13A is the lock state of the paper feeding operation, the detecting unit of the shield rib sensor 136 b set on the lower surface of the pressing tray 134 detects the shield rib 140 and generates a shield rib detection signal. The shield rib detection signal and the actuator detection signal are transmitted to the processor.

Third State of the Manual Paper Feed Unit 13 a

A third state of the manual paper feed unit 13A that cannot feed the recording sheets P to the image forming unit 24 and stores the recording sheets P is shown in FIG. 12. Specifically, the third state of the manual paper feed unit 13A is a state after the user places the recording sheets P on the manual paper feed unit 13A.

As shown in FIG. 12, in the third state of the manual paper feed unit 13A, as in the second state of the manual paper feed unit 13A, the downstream side of the pressing tray 134 is separated from the paper feeding roller 132 in the direction opposed to the bias direction Q. In the third state of the manual paper feed unit 13A, as shown in the figure, when the recording sheets P are stacked in the manual feed tray 131 and the pressing tray 134, the actuator 139 comes into contact with the end of the recording sheets P. Therefore, since the actuator 139 pivots in the opposite direction of the arrow R with the pivoting shaft 139 a as a fulcrum and retracts from the detecting unit of the actuator sensor 136 a set on the lower surface of the pressing tray 134, the detecting unit of the actuator sensor 136 a does not detect the actuator 139. Since the third state of the manual paper feed unit 13A is the lock state of the paper feeding operation, the detecting unit of the shield rib sensor 136 b detects the shield rib 140 and generates a shield rib detection signal. The shield rib detection signal is transmitted to the processor. In the image forming apparatus 10A according to the second embodiment, unlike the image forming apparatus 10 according to the first embodiment, it is possible to distinguish the second state and the third state of the manual paper feed unit 13A according to presence or absence of a detection signal of the actuator sensor 136 a.

Fourth State of the Manual Paper Feed Unit 13 a

A fourth state of the manual paper feed unit 13A that can feed the recording sheets P to the image forming unit 24 and stores the recording sheets P is shown in FIG. 13. Specifically, the fourth state of the manual paper feed unit 13A is a standby state for the start of copy.

As shown in FIG. 13, the fourth state of the manual paper feed unit 13A is the unlock state of the paper feeding operation. As in the first state of the manual paper feed unit 13A, the downstream side of the pressing tray 134 pivots in the direction of the paper feeding roller 132 with the pivoting shaft 134 a as a fulcrum with the biasing force of the pressing spring 134 b. In this case, the respective detecting units of the actuator sensor 136 a and the shield rib sensor 136 b set on the lower surface of the pressing tray 134 are separated from the actuator 139 and the shield rib 140. Since the recording sheets P are present on the pressing tray 134, the top of the recording sheets P on the pressing tray 134 comes into direct contact with the paper feeding roller 132.

In the fourth state of the manual paper feed unit 13A, since the recording sheets P are present on the pressing tray 134, the detecting unit of the actuator sensor 136 a set on the lower surface of the pressing tray 134 does not detect the actuator 139. Since the fourth state of the manual paper feed unit 13A is the unlock state of the paper feeding operation, the detecting unit of the shield rib sensor 136 b set on the lower surface of the pressing tray 134 does not detect the shield rib 140.

FIG. 14 is a table of determination by the processor for each of the states of the manual paper feed unit 13A shown in FIGS. 10 to 13.

As shown in FIG. 14, when the actuator sensor 136 a of the manual paper feed unit 13A generates an actuator detection signal (ON) while the registration sensor 242 detects the recording sheet P (while the recording sheet P is fed) and the shield rib sensor 136 b does not detect the shield rib 140 (OFF), the processor determines that the manual paper feed unit 13A is in the first state. In that case, the processor notifies, via the operation unit 21, for example, the touch panel display, the user of a warning that the recording sheets P cannot be fed because the recording sheets P are not present.

When the sensors 136 a and 136 b of the manual feed unit 13A generate the detection signals (ON), respectively, while the registration sensor 242 does not detect the recording sheet P (while paper feeding is stopped), the processor determines that the manual paper feed unit 13A is in the second state and prevents the paper feeding operation by the paper feeding roller 132 from starting. In that case, the processor notifies, via the operation unit 21, for example, the touch panel display, the user of a warning that the recording sheets P cannot be fed because the recording sheets P are not present or the manual paper feed unit 13A is in the lock state of the paper feeding operation. To supply the recording sheets P, when the user operates the switching lever 138 to pivot the pressing tray 134 in the direction opposed to the bias direction Q by the pressing spring 134 b and separate the pressing tray 134 from the paper feeding roller 132 and hold the pressing tray 134 (the lock state of the paper feeding operation), the manual paper feed unit 13A shifts from the first state to the second state. Therefore, it is possible to recognize the lock state of the paper feeding operation distinguished from a sheet jam.

When the actuator sensor 136 a of the manual paper feed unit 13A does not generate an actuator detection signal while the registration sensor 242 does not detect the recording sheets P (while paper feeding is stopped) and the shield rib sensor 136 b generates a shield rib detection signal (ON), the processor determines that the manual paper feed unit 13A is in the third state and does not start the paper feeding operation by the paper feeding roller 132. In that case, the processor notifies, via the operation unit 21, for example, the touch panel display, the user of a warning that the recording sheets P cannot be fed because of the lock of the paper feeding operation. When the user supplies the recording sheets P on the manual feed tray 131, the manual paper feed unit 13A shifts from the second state to the third state. Therefore, it is possible to recognize the lock state of the paper feeding operation distinguished from a sheet jam. Further, after the recording sheets P are supplied, when the user pivots the switching lever 138, the manual paper feed unit 13A shifts from the third state to the fourth state.

When both the sensors 136 a and 136 b do not generate detection signals while the registration sensor 242 does not detect the recording sheets P (while paper feeding is stopped), the processor determines that the manual paper feed unit 13A is in the fourth state and stands by for the start of copy.

When the registration sensor 242 detects the recording sheet P after a predetermined time elapses from the start of paper feeding by the paper feeding roller 132 and both the sensors 136 a and 136 b do not generate detection signals during the detection, the processor determines that the manual paper feed unit 13A is feeding the recording sheets P and can feed the recording sheets P and continues the paper feeding by the paper feeding roller 132.

In a state of paper feeding in which both the sensors 136 a and 136 b do not generate detection signals, when the registration sensor 242 does not detect the recording sheet P (NO-SIGNAL) even if a predetermined time elapses after the driving of the paper feeding roller 132, the processor stops the paper feeding operation determining that the manual paper feed unit 13A shifts from the paper feeding state to a state of a paper jam.

In a state of paper feeding by the manual paper feed unit 13A, when the actuator sensor 136 a generates a detection signal, the manual paper feed unit 13A shifts to the first state. When the user desires to continue copying from the first state, the user only has to operate the switching lever 138, supply the recording sheets P, and then reset the manual paper feed unit 13A to the fourth state.

In the first state of the manual paper feed unit 13A, when the user inputs a restart instruction to the operation unit 21 or transmits a new job signal from the PC and designates manual feed copy, the processor determines that the recording sheets P are absent and informs the user to that effect.

In the second state of the manual paper feed unit 13A, when the user inputs a restart instruction to the operation unit 21 or transmits a new job signal from the PC and designates the manual feed copy, the processor determines that the manual paper feed unit 13A is in the state of absence of the recording sheets P and the lock state of the paper feeding operation and does not drive the paper feeding roller 132. Further, the processor notifies the user of a request for supply of the recording sheets P and a request for operation of the switching lever 138.

In the third state of the manual paper feed unit 13A, when the user inputs a restart instruction to the operation unit 21 or transmits a new job signal from the PC and designates the manual feed copy, the processor determines that the manual paper feed unit 13A is in the lock state of the paper feeding operation and does not drive the paper feeding roller 132. Further, the processor notifies the user of a request for operation of the switching lever 138.

The image forming apparatus 10A according to the second embodiment includes the actuator 139, the shield rib 140, the actuator sensor 136 a that detects the actuator 139, and the shield rib sensor 136 b that detects the shield rib 140. Therefore, the processor determines whether the paper feeding operation of the manual paper feed unit 13A is stopped because of the absence of the recording sheets P, because of only the lock of the paper feeding operation (the separation and holding of the pressing tray 134), because of the absence of the recording sheets P and the lock of the paper feeding operation, or because of a sheet jam and notifies the user of a result of the determination via the operation unit 21 or LAN connection.

With the image forming apparatus 10A according to the second embodiment, even when the recording sheets P are stacked to the upper limit in specifications of the manual feed tray 131, it is possible to prevent malfunction of the paper feeding roller 132 by providing the sensor 136 b that detects the separation and holding (the lock state) of the pressing tray 134. The processor can accurately determine a cause of the stop of the paper feeding operation of the manual paper feed unit 13A and notify the user of the cause. 

1. A manual paper feed device comprising: a manual feed tray configured to stack a sheet; a paper feeding roller configured to feed the sheets on the manual feed tray into an image forming unit; a pressing tray configured to stack the sheet, rotatably supported with a first pivoting shaft as a first fulcrum and a downstream side of which in a conveying direction of the sheet is biased to the paper feeding roller side; a bias releasing member configured to separate and hold the pressing tray in a direction opposed to the bias direction and release the biasing; a sensor configured to detect at least one of presence or absence of the sheet on the manual feed tray and a bias releasing state of the pressing tray; a switching member configured to switch a biasing state and the bias releasing state of the pressing tray, coupled to the bias releasing member; a first detected member rotatably supported with a second pivoting shaft as a second fulcrum in contact with the sheet on the pressing tray, and provided in a position detectable by the sensor when the sheet is not present on the pressing tray; and a second detected member provided in a position detectable by the sensor when the pressing tray is in the bias releasing state.
 2. The device according to claim 1, wherein the first detected member is biased and supported in one direction, and the sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates a detection signal.
 3. The device according to claim 1, wherein the first detected member is biased and supported in one direction, and the sensor detects the first detected member when the sheet is not present on the pressing tray in the biasing state of the pressing tray, and generates a detection signal.
 4. The device according to claim 1, wherein the sensor is set on a lower surface of the pressing tray.
 5. The device according to claim 1, further comprising a determining unit configured to determine, on the basis of a detection signal generated by the sensor, that the device is in a state in which the sheet is not present on the pressing tray or the bias releasing state of the pressing tray.
 6. The device according to claim 5, wherein the device includes a first sensor as the sensor that detects the first detected member and generates a first detection signal as the detection signal, and a second sensor as the sensor that detects the second detected member and generates a second detection signal as the detection signal.
 7. The device according to claim 6, wherein the first detected member is biased and supported in one direction, and the first sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates the first detection signal.
 8. The device according to claim 6, wherein the first sensor and the second sensor are set on a lower surface of the pressing tray.
 9. The device according to claim 6, further comprising a determining unit configured to determine that the device is in the state in which the sheet is not present on the pressing tray when only the first detection signal is generated, determine that the device is in the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray when the first detection signal and the second detection signal are generated, and determine that the device is in a state in which the sheet is present and the bias releasing state of the pressing tray when only the second detection signal is generated.
 10. An image forming apparatus including a manual paper feed device configured to be retractable in an apparatus main body, comprising: a manual feed tray configured to stack a sheet; a paper feeding roller configured to feed the sheet on the manual feed tray into an image forming unit; a pressing tray configured to stack the sheet, rotatably supported with a first pivoting shaft as a first fulcrum and a downstream side of which in a conveying direction of the sheet is biased to the paper feeding roller side; a bias releasing member configured to separate and hold the pressing tray in a direction opposed to the bias direction and release the biasing; a sensor configured to detect at least one of presence or absence of the sheet on the manual feed tray and a bias releasing state of the pressing tray; a switching member configured to switch a biasing state and the bias releasing state of the pressing tray, coupled to the bias releasing member; a first detected member rotatably supported with a second pivoting shaft as a second fulcrum in contact with the sheet on the pressing tray, and provided in a position detectable by the sensor when the sheet is not present on the pressing tray; a second detected member provided in a position detectable by the sensor when the pressing tray is in the bias releasing state; a determining unit configured to determine a state of the manual paper feed device on the basis of a detection signal of the sensor; and a notifying unit configured to notify a result of the determination by the determining unit.
 11. The apparatus according to claim 10, wherein the first detected member is biased and supported in one direction, and the sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates the detection signal.
 12. The apparatus according to claim 10, wherein the sensor is set on a lower surface of the pressing tray.
 13. The apparatus according to claim 10, wherein the determining unit determines, on the basis of the detection signal generated by the sensor, that the manual paper feed device is in a state in which the sheet is not present on the pressing tray or the bias releasing state of the pressing tray.
 14. The apparatus according to claim 10, further comprising a registration sensor configured to detect the sheet conveyed from the manual feed tray to registration rollers, wherein the determining unit determines that the manual paper feed device shifts to a state in which the sheet is not present on the pressing tray when the registration sensor detects the sheet and the sensor generates the detection signal, and that the manual paper feed device is in the bias releasing state of the pressing tray when the registration sensor does not detect the sheet and the sensor generates the detection signal.
 15. The apparatus according to claim 10, wherein the apparatus includes a first sensor as the sensor that detects the first detected member and generates a first detection signal as the detection signal, and a second sensor as the sensor that detects the second detected member and generates a second detection signal as the detection signal.
 16. The apparatus according to claim 15, wherein the first detected member is biased and supported in one direction, and the first sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates the first detection signal.
 17. The apparatus according to claim 15, wherein the first sensor and the second sensor are set on a lower surface of the pressing tray.
 18. The apparatus according to claim 15, wherein the determining unit determines that the manual paper feed device is in the state in which the sheet is not present on the pressing tray when only the first detection signal is generated, determines that the manual paper feed device is in the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray when the first detection signal and the second detection signal are generated, and determines that the manual paper feed device is in the bias releasing state of the pressing tray when only the second detection signal is generated.
 19. An image forming method comprising: generating a detection signal in at least one of a state in which the sheet is not present on a pressing tray of a manual paper feed device, that is biased to a paper feeding roller side with the sheet stacked thereon and a bias releasing state of the pressing tray; determining, on the basis of the detection signal, at least one of the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray; stopping driving of the paper feeding roller according to the determination; and notifying a result of the determination.
 20. The method according to claim 19, wherein, when the detection signal includes a first detection signal indicating a state in which the sheet is not present on the pressing tray in the pressing tray biasing state, and a second detection signal indicating the bias releasing state of the pressing tray, it is determined on the basis of the detection signals that the manual paper feed device is in the state in which the recording sheet is not present on the pressing tray or the bias releasing state of the pressing tray. 